PatentDe  


Dokumentenidentifikation EP0807481 11.04.2002
EP-Veröffentlichungsnummer 0807481
Titel Werkzeughaltevorrichtung
Anmelder Sugino Corp., Schaumburg, Ill., US
Erfinder Sugino, Shigeru, Cyofu-city, Tokyo, JP;
Ishikawa, Kazuyuki, Toyama city, Toyama Pref. 936, JP
Vertreter Fuchs, Mehler, Weiss & Fritzsche, 65189 Wiesbaden
DE-Aktenzeichen 69619652
Vertragsstaaten CH, DE, FR, GB, IT, LI
Sprache des Dokument EN
EP-Anmeldetag 29.10.1996
EP-Aktenzeichen 963078159
EP-Offenlegungsdatum 19.11.1997
EP date of grant 06.03.2002
Veröffentlichungstag im Patentblatt 11.04.2002
IPC-Hauptklasse B23B 31/08
IPC-Nebenklasse B23G 1/46   B23G 5/20   

Beschreibung[en]
Field of the Invention

This invention is directed to a tool attachment assembly according to the preamble of claim 1 and as known from US-A- 4,514,115.

Background of the Invention

A threaded bore is commonly formed using a two-step process. First, a bore is formed using a process such as drilling, wherein a drill bit is applied to a workpiece and driven about its central axis to remove material from the workpiece at the desired location of the bore. Second, threads are formed in the bore using a process such as tapping, wherein a tapping tool is passed into the bore and driven about its central axis to remove additional material and form teeth, preferably with the central axis of the tapping tool aligned with the path of the central axis of the drill.

Each of these two machining processes, drilling and tapping, requires a tool attachment assembly with widely differing performance characteristics. For example, the drilling process requires the tool attachment assembly to fixedly hold the drill so as to minimize the uncontrolled movement of the drill relative to the tool attachment assembly. The translation of a central axis of the drill (and thus a central axis of the bore as formed) relative to a central axis for the bore as planned is highly undesirable. If the distance between the central axis of the bore as formed and the central axis of the bore as planned is large enough with respect to the tolerances involved, the workpiece may have to be scrapped. Even if the distance between the central axis of the bore as formed and the central axis of the bore as planned is within desired tolerances, relatively slight differences between the bore as planned and the bore as formed will require that the tapping process used to form the threads in the bore be capable of translating a central axis of the tapping tool relative to the central axis of the bore as planned so as to prevent damage or even destruction of the tapping tool. Thus, to avoid these undesirable results, a preferred drill attachment assembly will hold the drill bit substantially fixed.

By contrast, a preferred tapping tool attachment assembly will allow the tapping tool to move, or float, relatively freely radially relative to, as well as axially along, the central axis of the tool attachment assembly. Radial movement, or float, may be characterized as translational movement of the central axis of the tool radially relative to the central axis of the tool attachment assembly. Radial movement is desirable to prevent damage to the tapping tool when the process used to form the bore does not exactly align the central axis of the bore as formed with the central axis of the bore as planned. Consequently, radial float also allows for greater tolerances to be used with respect to the placement of the bore, if desirable and permissible with respect to the tolerances for the workpiece as a whole. Various examples of designs incorporating radial float are disclosed in U.S. Patent Nos. 4,111,442; 4,439,075; and 4,547,101.

Axial float is also desirable in a tapping tool attachment assembly. In operation, for a fixed rotational speed of the tapping tool about its central axis, the feed rate of the tapping tool into the workpiece is commonly greater than the feed rate of the tool holding assembly. To accommodate the differences in feed rate, special (and relatively expensive) equipment can be purchased to synchronize the feed rate of the tool assembly and the rotational speed of the tapping tool to prevent separation of the tool from the tool attachment assembly, or damage to the tapping tool. Alternatively, the tool holding assembly can be designed to allow the tapping tool to revolve at a fixed rotational speed and to move axially at its own feed rate relative to the tool attachment assembly. Various designs incorporating such a form of axial float can be found in U.S. Patent Nos 4,364,694 and 4,514,115.

For example, U.S. Patent No 4,514,115 discloses a tap holder that permits axial float of a tap relative to a body 1 controlled by a compression spring. However, a further separate drilling tool is required to initially drill the hole to be tapped.

Given that the drill attachment assembly preferably maintains the tool in a substantially fixed position relative to the tool holding assembly, and the tapping tool attachment assembly preferably allows the tool to move substantially freely relative to the tool holding assembly, these two machining processes are commonly performed using two different tool attachment assemblies. Thus, as a further consequence, the two-step process of making a threaded bore is commonly carried out by changing the tool attachment assembly after drilling and before tapping, or by performing the drilling on one machine and the tapping on another.

Either way, whether by changing tool attachment assemblies or by using two different machines, the costs of production are increased and productivity is decreased. For example, if the tool attachment assembly is changed between processes, time will be lost detaching the drill attachment assembly, attaching the tapping tool attachment assembly, and then centering the tapping tool such that the central axis of the tapping tool is substantially aligned with the central axis of the bore as planned. If two different machines are used, then time will be lost transporting the workpiece from one machine to the second, and then centering the workpiece such that the central axis of the tapping tool is substantially aligned with the central axis of the bore as planned. Even if a machining center is used in place of more conventional free-standing vertical or horizontal spindle machines, there will still be time lost changing tools. As the time lost increases, and the chances of misalignment and forming error increase, the costs of production will increase and/or the level of productivity may decrease.

Summary of the Invention

In one form of the invention, a tool attachment assembly is provided having a housing with a central axis, a toolholder with a tool carrying portion and a mounting portion spaced axially from the tool carrying portion, a projection on one of the housing and mounting portion of the tool holder, and a receptacle on the other of the housing and mounting portion of the tool holder for receiving the projection so that the housing and the tool holder reside at least partially, one within the other, with the tool holder in an operative state on the housing. There are axially facing first and second surfaces, one each on the housing and the mounting portion of the tool holder, that extend at least partially around the central axis and are abuttable to each other to limit movement of the tool holder axially towards the housing with the tool holder in the operative state. At least one of the first and second surfaces is other than parallel to a plane that is orthogonal to the central axis.

The first and second surfaces may extend fully around the central axis.

One or both of the first and second surfaces may be planar, as viewed in cross section.

In one form, the first surface is at a first acute angle to the central axis, with the second surface at a second acute angle which is supplementary to the first angle.

The projection and receptacle are relatively dimensioned so that the tool holder and housing are movable in a radial direction relative to each other with the tool holder and housing in one relative axial position, as described below. In one form, the projection has an annular outer surface and the receptacle an annular inner surface which, with the projection centered in the receptacle, are spaced from each other radially a distance between 0.00686 and 0.04064 mm (0.00027 and 0.0016 inches).

In one form, the first and second surfaces are abuttable to each other to limit radial movement of the tool holder relative to the housing with the tool holder in the operative state and in a first axial position relative to the housing. The first and second surfaces may be shaped to cause the tool holder to consistently align radially relative to each other as the tool holder is moved from a second axial position relative to the housing, wherein the first and second surfaces do not abut, into the first position. The tool holder and housing may align with their axes substantially coincident. The surfaces may cause the tool holder to be substantially fixed radially relative to the housing as the tool holder moves from the second position into the first position.

The tool holder may be limited in axial movement away from the housing. In one form, this is accomplished by providing a pin on one of the tool holder and housing and an elongate slot in the other of the tool holder and housing for receiving the pin. The elongate slot is bounded by a surface that abuts to the pin.

The tool holder may normally be biased towards the housing. This may be accomplished by a spring element.

In one form, the tool holder has a second receptacle bounded by an axially facing surface and the spring resides at least partially in the second receptacle and is compressed between the pin and the axially facing surface bounding the second receptacle.

The tool assembly may be provided in combination with a tool having a rotational axis, a first drill portion, and a second tapping portion spaced axially relative to the first drill portion. The tool is maintained in an operative position on the tool holder. The tool holder is in the first axial position relative to the housing with the first and second surfaces abutted to each other and the second axial position relative to the housing with the tool holder moved axially away from the housing so that the first and second surfaces do not abut to each other. The housing and tool holder are relatively dimensioned to allow the tool holder to move radially relative to each other with the tool holder in the second position.

Preferably, a tool attachment assembly is provided further comprising a housing and tool holder, each with a central axis, with there being structure cooperating between the housing and tool holder for maintaining the tool holder in an operative state on the housing and for guiding movement of the tool holder axially relative to the housing between a) a first position, wherein relative radial movement between the housing and tool holder is substantially prevented and b) a second position, wherein the tool holder can float radially relative to the housing.

The invention is also directed to a method of forming a threaded bore, which method includes the steps of providing a tool attachment assembly according to the above invention having a housing with a first central axis, a rotary tool on the tool holder and having a drill portion and a tapping portion, and structure cooperating between the housing and tool holder for maintaining the tool holder in an operative state on the housing and for guiding movement of the tool holder axially relative to the housing between a) a first position wherein radial movement between the housing and the tool holder is substantially prevented and b) a second position wherein the tool holder can float radially relative to the housing. The method further includes the step of rotating the tool holder at a first speed while advancing the housing in a first direction at a first rate to cause the drill portion to produce a bore in the workpiece and thereafter advancing the tapping portion into the workpiece bore with the tool holder rotating at the first speed and advancing in the first direction at the first rate so that the tapping portion engages the workpiece and as a result advances in the first direction at a rate greater than the first rate to thereby move the tool holder into the second position in which it can float. The tool can then be withdrawn from the workpiece.

Brief Description of the Drawings

  • Fig. 1 is a partial cross-sectional view of one embodiment of a tool attachment assembly, including a cooperating tool holder and housing, according to the present invention, with the tool holder in a first position relative to the housing and with the tool attachment assembly operatively connected to an automated drilling head;
  • Fig. 2. is a view as in Fig. 1 with the tool attachment assembly separated from the drilling head;
  • Fig. 3 is a view as in Fig. 2 with the tool holder in its extrememost extended position relative to the housing;
  • Fig. 4 is a cross-sectional view of another embodiment of the present invention configured to be used with a conventional drilling machine; and
  • Fig. 5 is a cross-sectional view of a further embodiment of the present invention configured to be used with a machining center with an automatic tool changer.

Description of the Preferred Embodiments

A preferred embodiment of the present invention is configured to be used with an automated drilling head 8, for example, the electric drilling head described in U.S. Patent No. 4,902,176. This drilling head 8 is partially shown in Fig. 1. According to the invention, a tool 10 is secured in an operative position at a first end 12 of a floating tool holder 14. The tool holder 14 has a tool carrying portion 15 at its leading end and a mounting portion at its other end 16. A projection 17 on the tool holder 14 is disposed within a receptacle 18 at a first end 20 of a housing 22 with the tool holder 14 in an operative state on the housing 22. In turn, a second end 24 of the tool holder housing 22 is disposed within a receptacle 26 of a ram 28 on the drilling head 8. The ram 28 is disposed within a receptacle 30 in a body 32 on the drilling head 8. Alternatively, the projection 17 may be on the housing 22 and the receptacle 18 on the tool holder 14, as known to those of ordinary skill in the art.

In operation, the tool holder housing 22 is driven by the drilling head 8 via a drive sleeve 34, attached at the second end 24 of the tool holder housing 22 by means of threads 36. As the sleeve 34 rotates, the rotational motion is transmitted to the tool holder housing 22 via the threads 36.

The rotational motion of the tool holder housing 22 is transmitted to the floating tool holder 14 via a drive pin 38. The drive pin 38 passes through a pair of diametrically opposite bores 40 in the tool holder housing 22 and a pair of elongate slots 42 in the floating tool holder 14. The drive pin 38 is secured at both ends to the tool holder housing 22 by means of a retaining ring 44 seated in a groove 46 in the exterior surface of the tool holder housing 22. While the drive pin 38 transmits the rotational motion of the tool housing 22 to the floating tool holder 14 via interaction with the sides 47 of the elongate slots 42, the floating tool holder 14 is free to extend and retract axially along its central axis relative to the holder housing 22 because the elongate slots 42 are preferably longer in the axial direction than the drive pin 38 is wide.

To secure the tool 10 to the tool holder 14, a collet 48 is disposed within a receptacle 50 at the first end 12 of the floating tool holder 14, and the tool 10 is disposed within the collet 48. The collet 48 is releasably held in the receptacle 50 using a collet nut 52 secured to the first end 12 of the floating tool holder 14 by means of threads. Using the collet 48, a number of different tools, such as drills and tapping tools, can be removably secured to the floating tool holder 14.

In performing a drilling operation with the embodiment of the present invention shown in Figs. 1 and 2, the central axis of the tool 10 is held substantially fixed relative to the central axis of the tool holder 14. Preferably, the tool holder 14 has a surface 54 which abuts against a surface 56 at the first end 20 of the tool holder housing 22. As shown in Fig. 2, the surface 54 is preferably beveled at an angle &thetas; to the central axis of the tool holder 14, and the surface 56 is preferably beveled at the supplementary angle α to the angle &thetas;. These surfaces 54, 56 are flat, as viewed in cross section. Preferably, the angle &thetas; is between 60-61 degrees, most preferably 60 degrees, and the angle α is between 119-120 degrees, most preferably 120 degrees. Alternatively, the surfaces 54, 56 may be manufactured using other shapes, for example, complementary curved surfaces or any other cooperating arrangement that prevents radial shift with the surfaces 54, 56 engaged.

The interaction of the surfaces 54, 56 limits movement of the tool holder 14 towards the housing 22 in a first direction, shown by an arrow 62, opposite a feed direction of the tool holder housing 22, as shown by an arrow 64. The interaction of the surfaces 54, 56 also serves to center the tool 10 within the recess 50 of the floating tool holder 14, so as to preferably maintain a common central axis for the tool 10, the tool holder 14 and the automated drilling head 8.

In performing a tapping operation, the tool 10 attached to the floating tool holder 14 is allowed to move, or float, both radially relative to the central axis of the tool holder housing 22, with the surfaces 54, 56 in non-abutting relationship as shown in Fig. 3, and axially along the central axis of the tool holder housing 22 and lines parallel to the central axis. Preferably, a slight radial spacing 66 exists between the outer annular surface of the tool holder 14 and the inner annular surface of the tool holder housing 22 to allow for translational motion of the tool 10 secured to the tool holder 14 radially relative to the central axis of the tool holder housing 22. Most preferably, the radial spacing 66 is between 0.00686 and 0.04064 mm (0.00027 and 0.0016 inches).

Additionally, the tool holder 14 is allowed to move axially relative to the housing 22 in the feed direction of the tool 10, as shown by the arrow 64, at a feed rate greater than that of the tool holder housing 22 because the tool holder 14 is not secured axially relative to the tool holder housing 22. Instead, the tool holder 14 is secured to the tool holder housing 22 through the drive pin 38, which is disposed through the elongate slots 42 in the tool holder 14. Because the elongate slots 42 are longer in the axial direction than the width of the drive pin 38, the tool holder 14 is allowed to extend and retract along the central axis relative to the tool holder housing 22, and lines parallel to the central axis. This movement is limited in the direction shown by the arrow 62 by the mating surfaces 54, 56, as shown in Fig. 2, and in the direction shown by the arrow 64 by the interaction of the drive pin 38 and the inwardmost surface 68 of the elongate slots 42, as shown in Fig. 3.

A spring 70 is disposed in the receptacle 72 of the tool holder 14 to act between the drive pin 38 and a surface at the end 16 of the tool holder 14. The spring 70 is provided to ensure that the tapping tool engages the threaded bore on the return stroke of the automated drilling head 8, and that upon complete withdrawal of the tool 10 from the tapped hole the tool 10 is automatically centered and readied for the next cycle.

Most preferably, the drilling and tapping operations can be performed without changing tools through the use of a tool commercially available from Cutting Tools, Inc. under the trademark DRAP, as shown attached to the embodiments of the present invention in Figs. 1-5. The DRAP tool has an initial portion 74 preferably shaped as a two-fluted twist drill, and is used to remove material to form the bore. The subsequent, intermediate portion 76 is shaped as a tapping tool, preferably with up to four flutes and a plurality of cutting teeth, to immediately tap the drilled portion of the bore as the tool advances further into the workpiece. The remaining, distal portion 78 of the tool is formed as a straight shank to be disposed within the collet 48. By using a DRAP tool, instead of separate conventional drill bits and tapping tools, a threaded bore can be machined in a single operation with a single pass of an automated drilling head, drill press or machining center without the need to change tools, tool attachment assemblies, or machines.

At the initiation of a combined drilling and tapping operation, the tool holder 14 is situated in a first axial position relative to the housing 22, as shown in Fig. 2, wherein the tool holder surface 54 facially abuts to the housing surface 56. The tool 10 is rotated at a first speed and advanced axially toward a workpiece, i.e. right to left in Fig. 1, by the drilling head 8 at a first rate. As the drilling head 8 effects advancement, the coaction between the surfaces 52, 54 causes the central axis of the tool holder 14 and housing 22 to become and remain substantially coincident. Radial movement of the tool holder 14 relative to the housing is substantially prevented with the tool holder 14 in the first position.

Once the drill portion 74 penetrates the workpiece to a predetermined depth, the tapping portion 76 engages the workpiece. As the tapping portion 76 engages the workpiece the tool 10 is caused to advance at a second rate that is greater than the rate of advancement of the tool holder by the drilling head 8. As a result, the tool holder 14 moves into a second axial position relative to the housing 22, as shown in Fig. 3, wherein the tool holder surface 54 separates from the housing surface 56. In the second position the tool holder 14 can float radially relative to the housing 22 to move into the bore even if there is a slight misalignment therewith.

Once the tool 10 is extracted from the workpiece, the tool holder 14 is driven by the spring 70 back to its first position in preparation for the next cycle.

While Figs. 1-3 show a preferred embodiment of the present invention configured to be used with an automated drilling head, the present invention is not limited to such an application. Fig. 4 shows an alternative embodiment of the invention configured to be used with ASA-type straight-shank machine tools. Fig. 5 shows an alternative embodiment of the invention configured with a V-flange tapered shank for use with machining centers with automatic tool changers.

Still other aspects, objects, and advantages of the present invention can be obtained from a study of the specification, the drawings, and the appended claims.


Anspruch[de]
  1. Werkzeughaltevorrichtung, umfassend:
    • ein-Gehäuse (22) mit einer zentralen Achse;
    • einen Werkzeughalter (14) mit einem werkzeugtragenden Teil (15) und einem Lagerteil (16), der axial von dem werkzeugtragenden Teil (15) beabstandet ist;
    • einen Ansatz (17) an dem Gehäuse (22) oder dem Lagerteil (16) des Werkzeughalters (14); und
    • eine Aufnahme (18) an dem Gehäuse (22) oder dem Lagerteil (16) des Werkzeughalters zur Aufnahme des Ansatzes (17), so daß sich von dem Gehäuse (22) und dem Werkzeughalter (14) wenigstens eines teilweise innerhalb des anderen befindet, wenn sich der Werkzeughalter (14) in einem Betriebszustand in dem Gehäuse befindet,
    gekennzeichnet dadurch, daß es axial gegenüberliegende erste und zweite Flächen (54, 56) jeweils an dem Gehäuse (22) und dem Lagerteil (16) des Werkzeughalters (14) gibt, daß sich jede zumindest teilweise um die zentrale Achse erstreckt und miteinander in Anschlag bringbar sind, um die Bewegung des Werkzeughalters axial gegen das Gehäuse (22) zu begrenzen, wenn sich der Werkzeughalter im Betriebszustand befindet;

    daß wenigstens eine der ersten (54) und zweiten (56) Flächen anders als parallel zu einer Ebene ist, die senkrecht zu der zentralen Achse steht.
  2. Werkzeughaltevorrichtung nach Anspruch 1, wobei die erste Oberfläche (54) eine im wesentlichen planare Oberfläche, betrachtet im Querschnitt, umfaßt.
  3. Werkzeughaltevorrichtung nach Anspruch 1 oder 2, wobei die zweite Fläche (56) eine im wesentlichen planare Oberfläche, betrachtet im Querschnitt, umfaßt.
  4. Werkzeughaltevorrichtung nach Anspruch 2 und 3, wobei sich die erste Fläche (54) unter einem ersten Winkel (&thetas;) zu der zentralen Achse befindet und sich die zweite Fläche (56) unter einem zweiten Winkel (α) zu der zentralen Achse befindet, der im wesentlichen supplementär zu dem ersten Winkel ist.
  5. Werkzeughaltevorrichtung nach Anspruch 4, wobei sich die ersten (54) und zweiten (56) Flächen im wesentlichen vollständig um die zentrale Achse erstrecken.
  6. Werkzeughaltevorrichtung nach irgendeinem vorhergehenden Anspruch, wobei der Ansatz (17) und die Aufnahme (18) in bezug aufeinander so dimensioniert sind, daß der Werkzeughalter (14) und das Gehäuse (22) in einer radialen Richtung relativ zueinander beweglich sind, wenn sich der Werkzeughalter (14) im Betriebszustand befindet.
  7. Werkzeughaltevorrichtung nach Anspruch 6, wobei der Ansatz (17) eine ringförmige Außen-Oberfläche und die Aufnahme eine ringförmige Innen-Oberfläche besitzt und daß bei in der Aufnahme zentriertem Ansatz ein Raum zwischen der äußeren Ansatz-Oberfläche und der inneren Aufnahme-Oberfläche besteht.
  8. Werkzeughaltevorrichtung nach Anspruch 7, wobei der Raum zwischen 0,00686 und 0,04064 mm (0,00027 und 0,0016 Zoll) liegt.
  9. Werkzeughaltevorrichtung nach irgendeinem vorhergehenden Anspruch, wobei die ersten und zweiten Flächen aneinander anschlagbar sind, um die Radialbewegung des Werkzeughalters (14) in bezug auf das Gehäuse zu begrenzen, wenn sich der Werkzeughalter (14) im Betriebszustand befindet.
  10. Werkzeughaltevorrichtung nach irgendeinem vorhergehenden Anspruch, ferner umfassend Mittel (38, 68), die zwischen dem Werkzeughalter (14) und dem Gehäuse (22) zusammenwirken, um die Axialbewegung des Werkzeughalters (14) weg von dem Gehäuse zu begrenzen.
  11. Werkzeughaltevorrichtung nach Anspruch 10, wobei die Begrenzungsmittel einen Stift (38) an dem Werkzeughalter (14) oder dem Gehäuse (22) und einen länglichen Schlitz (42) an dem jeweils anderen des Werkzeughalters (14) oder des Gehäuses (22) zur Aufnahme des Stiftes umfassen, wobei der längliche Schlitz durch eine Oberfläche (68) begrenzt ist, die an dem Stift (38) anschlägt.
  12. Werkzeughaltevorrichtung nach Anspruch 10 oder 11, umfassend ein Federelement (70), das zwischen dem Gehäuse (22) und dem Werkzeughalter (14) wirkt, um normalerweise den Werkzeughalter (14) axial gegen das Gehäuse (22) zu drücken.
  13. Werkzeughaltevorrichtung nach Anspruch 11 und 12, wobei das Federelement (70) an dem Stift (38) anliegt.
  14. Werkzeughaltevorrichtung nach Anspruch 12 oder 13, wobei der Werkzeughalter (14) eine zweite Aufnahme (72) besitzt, die durch eine axial gerichtete Oberfläche begrenzt ist, und daß die Feder (70) sich zumindest teilweise in der zweite Aufnahme befindet und zwischen dem Stift (38) und der axial gerichteten Oberfläche, die die zweite Aufnahme begrenzt, zusammengedrückt ist.
  15. Werkzeughaltevorrichtung nach irgendeinem vorhergehenden Anspruch in Kombination mit einem Werkzeug (10), das eine Rotationsachse, einen ersten Bohrteil (74) und einen zweiten Gewindeschneidteil (76), der axial in bezug auf den ersten Bohrteil beabstandet ist, besitzt, wobei zusammenwirkende Mittel zwischen dem Werkzeughalter (14) und dem Werkzeug (10) vorgesehen sind, um das Werkzeug in einer Betriebsposition an dem Werkzeughalter (14) zu halten, wobei sich der Werkzeughalter in a) einer ersten axialen Position in bezug auf das Gehäuse befindet, wenn die ersten (54) und zweiten (56) Flächen aneinander anschlagen und sich b) in einer zweiten axialen Position in bezug auf das Gehäuse befindet, wenn der Werkzeughalter (14) axial von dem Gehäuse wegbewegt ist, so daß die ersten (54) und zweiten (56) Flächen nicht aneinander anschlagen, wobei das Gehäuse und der Werkzeughalter in bezug aufeinander dimensioniert sind, um dem Werkzeughalter die relative Bewegung in bezug auf das Gehäuse zu gestatten, wenn sich der Werkzeughalter in der zweiten Position befindet.
  16. Werkzeughaltevorrichtung nach Anspruch 15, wobei die ersten (54) und zweiten (56) Flächen so geformt sind, um den Werkzeughalter (14) zu veranlassen, beständig radial in bezug aufeinander ausgerichtet zu sein, wenn der Werkzeughalter von der zweiten Position in die erste Position bewegt wird.
  17. Werkzeughaltevorrichtung nach Anspruch 16, wobei der Werkzeughalter eine zentrale Achse besitzt und die ersten (54) und zweiten (56) Flächen geformt sind, um den Werkzeughalter (14) zu veranlassen, beständig auf die im wesentlichen übereinstimmenden zentralen Achsen des Werkzeughalters (14) und des Gehäuses (22) ausgerichtet zu sein.
  18. Werkzeughaltevorrichtung nach Anspruch 15, 16 oder 17, wobei die ersten (54) und zweiten (56) Flächen geformt sind, um den Werkzeughalter (14) zu veranlassen, im wesentlichen radial starr in bezug auf das Gehäuse (22) zu sein, wenn der Werkzeughalter (14) von der zweiten Position in die erste Position bewegt wird.
  19. Werkzeughaltevorrichtung nach Anspruch 15, 16, 17 oder 18, wobei die ersten (54) und zweiten (56) Flächen im wesentlichen planar, betrachtet im Querschnitt, sind und sich jeweils im wesentlichen vollständig um die zentrale Achse erstrecken und wobei der Ansatz eine ringförmige Außen-Oberfläche und die Aufnahme eine ringförmige Innen-Oberfläche besitzt, wobei mit dem Werkzeughalter in der zweiten Position der Werkzeughalter radial in bezug auf das Gehäuse gleiten kann.
  20. Werkzeughaltevorrichtung nach irgendeinem vorhergehenden Anspruch, aufweisend:
    • ein Gehäuse (22) mit einer zentralen Achse;
    • einen Werkzeughalter (14) mit einer zentralen Achse; und gekennzeichnet durch
    • Mittel (54, 56), die zwischen dem Gehäuse (22) und dem Werkzeughalter (14) zusammenwirken, um den Werkzeughalter in einem Betriebszustand in dem Gehäuse (22) zu halten, und um die Bewegung des Werkzeughalters (14) axial in bezug auf das Gehäuse (22) zu führen zwischen a) einem ersten Teil, wobei die relative radiale Bewegung zwischen dem Gehäuse und dem Werkzeughalter (14) im wesentlichen verhindert wird und b) einem zweiten Teil, wobei der Werkzeughalter radial in bezug auf das Gehäuse gleiten kann.
  21. Werkzeughaltevorrichtung nach Anspruch 21 in Kombination mit einem Drehwerkzeug (10), das einen Bohrteil (74) und einen Gewindeschneidteil (76) besitzt, wobei, wenn der Bohrteil des Drehwerkzeuges in ein Werkstück eindringt und der Werkzeughalter sich in der ersten Position befindet, der Werkzeughalter (14) und das Gehäuse (22) eine im wesentlichen starre relative Position besitzen und wenn der Gewinde-Schneidabschnitt (76) in ein Werkstück eindringt und der Werkzeughalter (14) sich in der zweiten Position befindet, das Werkzeug radial relativ zu dem Gehäuse (22) gleiten kann.
  22. Verfahren zur Bildung einer Gewindebohrung, wobei das Verfahren die Schritte umfaßt:
    • Vorsehen einer Werkzeughaltevorrichtung gemäß irgendeinem vorhergehenden Anspruch, umfassend ein Gehäuse (22) mit einer zentralen Achse; ein Drehwerkzeug (10) mit einem Bohrteil (74) und einem Gewindeschneidteil (76); und gekennzeichnet durch Mittel, die zwischen dem Gehäuse (22) und dem Werkzeughalter (14) zusammenwirken, um den Werkzeughalter in einem Betriebszustand an dem Gehäuse zu halten und zum Führen einer Relativbewegung des Werkzeughalters axial in bezug auf das Gehäuse zwischen a) einer ersten Position, bei der eine relative Radialbewegung zwischen dem Gehäuse und dem Werkzeughalter im wesentlichen verhindert wird und b) einer zweiten Position, bei der der Werkzeughalter radial in bezug auf das Gehäuse gleiten kann;
    • Rotieren des Werkzeughalters (14) mit einer ersten Geschwindigkeit während das Gehäuse (22) in einer ersten Richtung mit einer ersten Geschwindigkeit vorgeschoben wird, um den Bohrteil (74) zu veranlassen, in der ersten Richtung mit der ersten Geschwindigkeit vorgeschoben zu werden und eine Bohrung in dem Werkstück zu erzeugen;
    • Bildung von Gewinden innerhalb der Bohrung durch Vorschieben des Gewindeschneidteiles (76) in die Werkstückbohrung, wobei der Werkzeughalter (14) mit der ersten Geschwindigkeit rotiert und in der ersten Richtung mit der ersten Geschwindigkeit vorgeschoben wird, so daß der Gewindeschneidteil (76) mit dem Werkstück in Eingriff gelangt und infolgedessen in der ersten Richtung mit einer Geschwindigkeit größer als die erste Geschwindigkeit vorgeschoben wird, wobei der Werkzeughalter (14) in die zweite Position bewegt wird; und
    • Rückziehen des rotierenden Werkzeuges (10) aus dem Werkstück.
Anspruch[en]
  1. A tool attachment assembly comprising:
    • a housing (22) having a central axis;
    • a tool holder (14) having a tool carrying portion (15) and a mounting portion (16) spaced axially from the tool carrying portion (15);
    • a projection (17) on one of the housing (22) and the mounting portion (16) of the tool holder (14); and
    • a receptacle (18) on the other of the housing (22) and the mounting portion (16) of the tool holder for receiving the projection (17) so that the housing (22) and the tool holder (14) reside at least partially, one within the other, with the tool holder (14) in an operative state on the housing,
       characterised by there being axially facing first and second surfaces (54, 56), one each on the housing (22) and the mounting portion (16) of the tool holder (14), that each extend at least partially around the central axis and are abutable to each other to limit movement of the tool holder axially towards the housing (22) with the tool holder in the operative state,

       at least one of the first (54) and second (56) surfaces being other than parallel to a plane that is orthogonal to the central axis.
  2. The tool attachment assembly according to claim 1, wherein the first surface (54) comprises a substantially planar surface, as viewed in cross section.
  3. The tool attachment assembly according to claim 1 or 2, wherein the second surface (56) comprise substantially planar surfaces as viewed in cross section.
  4. The tool attachment assembly according to claim 2 and 3, wherein the first surface (54) is at a first angle (&thetas;) to the central axis, and the second surface (56) is at a second angle, (α) which is substantially supplementary to the first angle, to the central axis.
  5. The tool attachment assembly according to claim 4, wherein the first (54) and second (56) surfaces extend substantially fully around the central axis.
  6. The tool attachment assembly according to any preceding claim, wherein the projection (17) and the receptacle (18) are relatively dimensioned so that the tool holder (14) and housing (22) are movable in a radial direction relative to each other with the tool holder (14) in the operative state.
  7. The tool attachment assembly according to claim 6 wherein the projection (17) has an annular outer surface and the receptacle has an annular inner surface and with the projection centered in the receptacle there is a space between the outer projection surface and inner receptacle surface.
  8. The tool attachment assembly according to claim 7, wherein the space is between 0.00686 and 0.04064 millimetres (0.00027 and 0.0016 inches).
  9. The tool attachment assembly according to any preceding claim, wherein the first and second surfaces are abutable to each other to limit radial movement of the tool holder (14) relative to the housing with the tool holder (14) in the operative state.
  10. The tool attachment assembly according to any preceding claim, further comprising means (38, 68) cooperating between the tool holder (14) and housing (22) for limiting axial movement of the tool holder (14) away from the housing.
  11. The tool attachment assembly according to claim 10 wherein the limiting means comprises a pin (38) on one of the tool holder (14) and housing (22) and an elongate slot (42) on the other of the tool holder (14) and housing (22) for receiving the pin, said elongate slot being bounded by a surface (68) that abuts to the pin (38).
  12. The tool attachment assembly according to claim 10 or 11 including a spring element (70) acting between the housing (22) and tool holder (14) for normally urging the tool holder (14) axially towards the housing (22).
  13. The tool attachment assembly according to claim 11 and 12 wherein the spring element (70) abuts to the pin (38).
  14. The tool attachment assembly according to claim 12 or 13 wherein the tool holder (14) has a second receptacle (72) bounded by an axially facing surface and the spring resides (70) at least partially in the second receptacle and is compressed between the pin (38) and the axially facing surface bounding the second receptacle.
  15. The tool attachment assembly according to any preceding claim in combination with a tool (10) having a rotational axis, a first drill portion (74) and a second tapping portion (76) spaced axially relative to the first drill portion, with there being means cooperating between the tool holder (14) and tool (10) for maintaining the tool in an operative position on the tool holder (14), said tool holder being in a) a first axial position relative to the housing with the first (54) and second (56) surface abutted to each other and b) a second axial position relative to the housing with the tool holder (14) moved axially away from the housing so that the first (54) and second (56) surfaces do not abut to each other, said housing and tool holder being relatively dimensioned to allow the tool holder to move radially relative to the housing with the tool holder in the second position.
  16. The tool attachment assembly according to claim 15 wherein the first (54) and second (56) surfaces are shaped to cause the tool holder (14) to consistently align radially relatively to each other as the tool holder is moved from the second position into the first position.
  17. The tool attachment assembly according to claim 16 wherein the tool holder has a central axis and the first (54) and second (56) surfaces are shaped to cause the tool holder (14) to consistently align with the central axes of the tool holder (14) and housing (22) substantially coincident.
  18. The tool attachment assembly according to claim 15, 16 or 17 wherein the first (54) and second (56) surfaces are shaped to cause the tool holder (14) to be substantially fixed radially relative to the housing (22) as the tool holder (14) is moved from the second position into the first position.
  19. The tool attachment assembly according to claim 15, 16, 17 or 18 wherein the first (54) and second (56) surfaces are substantially planar as viewed in cross section and each extend substantially fully around the central axis, and wherein the projection has an annular outer surface and the receptacle has an annular inner surface and with the tool holder in the second position the tool holder can float radially relative to the housing.
  20. A tool attachment assembly according to any preceding claim comprising:
    • a housing (22) having a central axis;
    • a tool holder (14) having a central axis; and characterised by
    • means (54, 56) cooperating between the housing (22) and tool holder (14) for maintaining the tool holder in an operative state on the housing (22) and for guiding movement of the tool holder (14) axially relative to the housing (22) between a) a first portion, wherein relative radial movement between the housing and tool holder (14) is substantially prevented and b) a second position wherein the tool holder can float radially relative to the housing.
  21. The tool attachment assembly according to claim 21 in combination with a rotary tool (10) having a drill portion (74) and a tapping portion (76), whereupon with the drill portion of the rotary tool penetrating a workpiece with the tool holder in the first position, the tool holder (14) and housing (22) have a substantially fixed relative position and upon the tapping section (76) entering a workpiece with the tool holder (14) in the second position the tool can float radially relative to the housing (22).
  22. A method of forming a threaded bore, said method comprising the steps of:
    • providing a tool attachment assembly according to any preceding claim comprising a housing (22) having a central axis; a rotary tool (10) having a drill portion (74) and a tapping portion (76); and characterised by means cooperating between the housing (22) and tool holder (14) for maintaining the tool holder in an operative state on the housing and for guiding relative movement of the tool holder axially relative to the housing between a) a first position wherein relative radial movement between the housing and tool holder is substantially prevented and b) a second position wherein the tool holder can float radially relative to the housing; and
    • rotating the tool holder (14) at a first speed while advancing the housing (22) in a first direction at a first rate to cause the drill portion (74) to advance in the first direction at the first rate to produce a bore in the workpiece;
    • forming threads within the bore by advancing the tapping portion (76) into the workpiece bore with the tool holder (14) rotating at the first speed and advancing in the first direction at the first rate so that the tapping portion (76) engages the workpiece and as a result advances in the first direction at a rate greater than the first rate, thereby moving the tool holder (14) into the second position; and
    • withdrawing the rotary tool (10) from the workpiece.
Anspruch[fr]
  1. Dispositif de fixation d'outil, comprenant :
    • un carter (22) muni d'un axe central ;
    • un porte-outil (14) muni d'une partie de support d'outil (15) et d'une partie de monture (16) espacée axialement de la partie de support d'outil (15) ;
    • une saillie (17) sur l'un ou l'autre du carter (22) et de la partie de monture (16) du porte-outil (14) ; et
    • une cavité de réception (18) dans l'autre du carter (22) et de la partie de monture (16) du porte-outil, pour recevoir la saillie (17) de façon que le carter (22) et le porte-outil (14) se trouvent, au moins en partie, l'un dans l'autre lorsque le porte-outil (14) se trouve dans un état de fonctionnement sur le carter,
    caractérisé par
    • une première surface (54) et une seconde surface (56) se faisant face axialement, disposées respectivement sur le carter (22) et sur la partie de monture (16) du porte-outil (14), en s'étendant chacune au moins partiellement autour de l'axe central et en pouvant venir buter l'une contre l'autre pour limiter le mouvement axial du porte-outil vers le carter (22) lorsque le porte-outil se trouve dans l'état de fonctionnement,
    • l'une au moins de la première surface (54) et de la seconde surface (56) n'étant pas parallèle à un plan perpendiculaire à l'axe central.
  2. Dispositif de fixation d'outil selon la revendication 1,

    dans lequel

    la première surface (54) comprend une surface essentiellement plane dans une vue en coupe transversale.
  3. Dispositif de fixation d'outil selon la revendication 1 ou 2,

    dans lequel

    la seconde surface (56) comprend une surface essentiellement plane dans une vue en coupe transversale.
  4. Dispositif de fixation d'outil selon la revendication 2 ou 3,

    dans lequel

    la première surface (54) forme un premier angle (&thetas;) avec l'axe central, tandis que la seconde surface (56) forme, avec l'axe central, un second angle (α) qui est essentiellement supplémentaire du premier angle.
  5. Dispositif de fixation d'outil selon la revendication 4,

    dans lequel

    la première surface (54) et la seconde surface (56) s'étendent essentiellement complètement autour de l'axe central.
  6. Dispositif de fixation d'outil selon l'une quelconque des revendications précédentes,

    dans lequel

    la saillie (17) et la cavité de réception (18) sont dimensionnées l'une par rapport à l'autre de façon que le porte-outil (14) et le carter (22) puissent se déplacer dans une direction radiale l'un par rapport à l'autre lorsque le porte-outil (14) se trouve dans l'état de fonctionnement.
  7. Dispositif de fixation d'outil selon la revendication 6,

    dans lequel

    la saillie (17) présente une surface extérieure annulaire et la cavité de réception présente une surface intérieure annulaire, de façon que, lorsque la saillie est centrée dans la cavité de réception, il existe un espacement entre la surface extérieure de la saillie et la surface intérieure de la cavité de réception.
  8. Dispositif de fixation d'outil selon la revendication 7,

    dans lequel

    l'espacement est compris entre 0,00686 et 0,04064 millimètre (0,00027 et 0,0016 pouce).
  9. Dispositif de fixation d'outil selon l'une quelconque des revendications précédentes,

    dans lequel

    la première surface et la seconde surface peuvent venir buter l'une contre l'autre pour limiter le mouvement radial du porte-outil (14) par rapport au carter lorsque le porte-outil (14) se trouve dans l'état de fonctionnement.
  10. Dispositif de fixation d'outil selon l'une quelconque des revendications précédentes,

    comprenant en outre

    des moyens (38, 68) coopérant entre le porte-outil (14) et le carter (22) pour limiter le mouvement axial d'écartement du porte-outil (14) par rapport au carter.
  11. Dispositif de fixation d'outil selon la revendication 10,

    dans lequel

    les moyens de limitation comprennent une clavette (38) sur l'un ou l'autre du porte-outil (14) et du carter (22), ainsi qu'une fente allongée (42) sur l'autre du porte-outil (14) et du carter (22), pour recevoir la clavette, la fente allongée étant limitée par une surface (68) qui bute contre la clavette (38).
  12. Dispositif de fixation d'outil selon la revendication 10 ou 11, comprenant

    un élément de ressort (70) agissant entre le carter (22) et le porte-outil (14) pour pousser normalement le porte-outil (14) axialement vers le carter (22).
  13. Dispositif de fixation d'outil selon la revendication 11 ou 12,

    dans lequel

    l'élément de ressort (70) bute contre la clavette (38).
  14. Dispositif de fixation d'outil selon la revendication 12 ou 13,

    dans lequel

    le porte-outil (14) comporte une seconde cavité de réception (72) limitée par une surface faisant face axialement, et le ressort (70) se loge au moins partiellement dans la seconde cavité de réception, en étant comprimé entre la clavette (38) et la surface faisant face axialement, qui limite la seconde cavité de réception.
  15. Dispositif de fixation d'outil selon l'une quelconque des revendications précédentes,

    en combinaison avec

    un outil (10) comportant un axe de rotation, une première partie de foret (74) et une seconde partie de taraud (76) espacée axialement de la première partie de foret, tandis qu'on a des moyens coopérant entre le porte-outil (14) et l'outil (10) pour maintenir cet outil dans une position de fonctionnement sur le porte-outil (14), ce porte-outil (14) se trouvant dans :a) une première position axiale par rapport au carter, dans laquelle la première surface (54) et la seconde surface (56) butent l'une contre l'autre, et b) une seconde position axiale par rapport au carter, dans laquelle le porte-outil (14) est écarté axialement du carter de façon que la première surface (54) et la seconde surface (56) ne butent pas l'une contre l'autre, le carter et le porte-outil étant dimensionnés l'un par rapport à l'autre pour permettre au porte-outil de se déplacer radialement par rapport au carter lorsque le porte-outil se trouve dans la seconde position.
  16. Dispositif de fixation d'outil selon la revendication 15,

    dans lequel

    la première surface (54) et la seconde surface (56) sont formées pour amener le porte-outil (14) à les aligner radialement de manière uniforme l'une par rapport à l'autre lorsque le porte-outil se déplace pour passer de la seconde position à la première position.
  17. Dispositif de fixation d'outil selon la revendication 16,

    dans lequel

    le porte-outil comporte un axe central tandis que la première surface (54) et la seconde surface (56) sont formées pour amener le porte-outil (14) à les aligner uniformément lorsque les axes centraux du porte-outil (14) et du carter (22) sont essentiellement en coïncidence.
  18. Dispositif de fixation d'outil selon la revendication 15, 16 ou 17,

    dans lequel

    la première surface (54) et la seconde surface (56) sont formées pour amener le porte-outil (14) à être essentiellement fixé radialement par rapport au carter (22) lorsque le porte-outil (14) est déplacé pour passer de la seconde position à la première position.
  19. Dispositif de fixation d'outil selon la revendication 15, 16, 17 ou 18,

    dans lequel

    la première surface (54) et la seconde surface (56) sont essentiellement planes dans une vue en coupe transversale, chacune d'elles s'étendant essentiellement complètement autour de l'axe central, tandis que la saillie présente une surface extérieure annulaire, la cavité de réception présente une surface intérieure annulaire, et le porte-outil, dans sa seconde position, peut flotter radialement par rapport au carter.
  20. Dispositif de fixation d'outil selon l'une quelconque des revendications précédentes,

    comprenant :
    • un carter (22) muni d'un axe central ; et
    • un porte-outil (14) muni d'un axe central,
    caractérisé par

    des moyens (54 56) coopérant entre le carter (22) et le porte-outil (14) pour maintenir le porte-outil dans un état de fonctionnement sur le carter (22) et pour guider le mouvement du porte-outil (14) axialement par rapport au carter (22) entre :a) une première position dans laquelle le mouvement radial relatif entre le carter et le porte-outil (14) est essentiellement empêché, et b) une seconde position dans laquelle le porte-outil peut flotter radialement par rapport au carter.
  21. Dispositif de fixation d'outil selon la revendication 21,

    en combinaison avec

    un outil rotatif (10) comportant une partie de foret (74) et une partie de taraud (76), de façon que lorsque la partie de foret de l'outil rotatif pénètre dans une pièce d'oeuvre avec le porte-outil dans la première position, le porte-outil (14) et le carter (22) aient des positions relatives essentiellement fixes, et que lorsque la partie de taraud (76) pénètre dans la pièce d'oeuvre avec le porte-outil (14) dans la seconde position, ce porte-outil puisse flotter radialement par rapport au carter (22).
  22. Procédé de formation d'un trou taraudé,

    comprenant les étapes consistant à :
    • utiliser un dispositif de fixation d'outil selon l'une quelconque des revendications précédentes, comprenant un carter (22) muni d'un axe central, un outil rotatif (10) muni d'une partie de foret (74) et d'une partie de taraud (76), le dispositif se caractérisant par des moyens coopérant entre le carter (22) et le porte-outil (14) pour maintenir ce porte-outil dans un état de fonctionnement sur le carter, et pour guider le mouvement relatif du porte-outil axialement par rapport au carter entre a) une première position dans laquelle le mouvement radial relatif entre le carter et le porte-outil est essentiellement empêché, et b) une seconde position dans laquelle le porte-outil peut flotter radialement par rapport au carter ;
    • faire tourner le porte-outil (14) à une première vitesse tout en faisant avancer le carter (22) dans une première direction à un premier taux d'avance pour faire avancer la partie de foret (74) dans la première direction au premier taux d'avance, de manière à produire un alésage dans la pièce d'oeuvre ;
    • former un filetage à l'intérieur de l'alésage en faisant avancer la partie de taraud (76) dans l'alésage de la pièce d'oeuvre tandis que le porte-outil (14) tourne à la première vitesse et avance dans la première direction au premier taux d'avance, de façon que la partie de taraud (76) s'engage dans la pièce d'oeuvre et avance ainsi dans la première direction à un taux supérieur au premier taux d'avance, pour amener ainsi le porte-outil (14) dans la seconde position ; et
    • retirer l'outil rotatif (10) de la pièce d'oeuvre.






IPC
A Täglicher Lebensbedarf
B Arbeitsverfahren; Transportieren
C Chemie; Hüttenwesen
D Textilien; Papier
E Bauwesen; Erdbohren; Bergbau
F Maschinenbau; Beleuchtung; Heizung; Waffen; Sprengen
G Physik
H Elektrotechnik

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